适冷菌Pseudomonas extremaustralis PF中海藻糖的合成途径及TreS基因的克隆

通过对一株高寒冰缘植物内生适冷假单胞菌Pseudomonas extremaustralis PF的研究,发现该菌中同时存在TPS/TPP,TreY/TreZ和neS三种海藻糖合成途径,其中TreS途径的合成酶活性最高.对该菌的海藻糖合成酶TreS的基因进行克隆,得到一个新的TreS基因PFTreS,该基因与已报道的细菌TreS基因在核酸序列上表现出较高的同源性(最高达80.2%).根据基因序列预测的PFTreS氨基酸序列具有TreS酶的催化功能保守区,与假单胞菌P.fluorescens Pf-5的TreS有很高的同源性.这些结果表明了Pseudomonas extremaustralis中海藻糖的合成特性,为进一步揭示海藻糖的合成与Pseudomonas extremaustralis PF的低温响应机制的关系奠定了基础.

Trehalose synthesis pathways and characterization of TreS gene in psychrotrophic Pseudomonas extremaustralis PF

Trehalose in psychrotrophic Pseudomonas extremaustralis PF isolated from a kind of cryophyte was investigated. Three trehalose synthesis pathways were found in psychrotrophic Pseudomonas extremaustralis PF: TPS/TPP, TreY/TreZ and TreS. The dominant enzyme responsible for trehalose synthesis in Pseudomonas extremaustralis PF was TreS. A new TreS gene was cloned, which exhibited high nucleotide sequence identity compared to previously reported bacteria TreS genes (the highest identity was 80.2%).The predicted amino acid protein sequence of PFTreS had high homology with that of P. fluorescens Pf-5 TreS, which contained conserved domains related with catalytic and substrate binding of TreS. These results demonstrated the character of trehalose synthesis in Pseudomonas extremaustralis PF, which is important for future research about the role that trehalose may play in cold-resistance of Pseudomonas extremaustralis PF cells.